Helicascolide C, a new lactone from an Indonesian marine algicolous strain of Daldinia eschscholzii (Xylariaceae, Ascomycota)

► A new lactone, helicascolide C was isolated from an endophytic fungus. ► The compound showed fungistatic activity against the phytopathogenic fungus Cladosporium cucumerinum. ► The fungus was isolated from Gracilaria sp. SGR-1, collected from the coast of South Sulawesi, Indonesia. ► Using DNA-based taxonomy, the fungus was identified as Daldinia eschscholzii strain.